As is well known in the circuit card connecting art, circuit cards made to the identical dimensional specifications will nevertheless vary in width, length and thickness without exceeding manufacturing tolerances. Accordingly, a card slot in a card edge connector must be capable of accepting cards of varying dimensions such that the connector's contact elements accurately engage the proper conductive pads on the edge of the card. One method of achieving this is to bias the card against one end of the card slot; i.e., the datum point. Prior art devices for accomplishing this biasing employ a spring at the opposite end of the slot. Such springs, however, suffer a drawback in that they do not care whether the card is being inserted or withdrawn on a straight line or obliquely. In the latter case, contact elements will engage different pads and, in a power situation, damage can occur to electronic components on the card. Another drawback with springs is that they tend to take a set and lose their ability to properly bias the card against the referenced end.
A solution to these and other problems was found and is disclosed in U.S. Pat. No. 4,477,138, which is incorporated herein by reference. The solution was to provide a sliding member in a passage having a sloping transverse wall at the end of the slot with the member being biased towards the top surface of the connector. The sliding member, or wedge, is driven down the passage by a card being inserted a distance sufficient enough to accommodate the width of that card. Further, a card can only be inserted in a straight line into or from the slot. Since the wedge was not spring biased into the slot, the aforementioned set in spring resiliency is not a problem. The card biasing device of U.S. Pat. No. 4,477,138, shown in FIG. 1 herein, has met with industry acceptance and is commercially successful.
As noted above, the wedge is biased upwardly in its passage with the biasing being provided by a coil spring. Further, the wedge is molded from a plastics material; e.g., polyphenylene oxide. It is now proposed to stamp and form the wedge from a metal and incorporate therein an integral biasing member for urging the wedge upwardly in the passage.